Switch



Patented Dec. 12, 1933 UNITED STATES PATENT OFFICE,

SWITCH Application September 6, 1930. Serial No. 480,154

B Claims.

This invention relates to switches, and with regard to certain morespecific features to 'contacts for switches.

Among the several objects of the invention may be noted the provision ofa resiliently mounted contact which has a general application, but whichalso has a particularly advantageous application to switches having twoor more contact points, especially snapping disc types; the provision ofa contact of this class which tends to equalize contact pressure and itsresulting eiect upon that which supports said contact; and the provisionof a device of the class described which is compact in form and whichmay be simply fabricated. Other objects will be in part obvious and inpart pointed out hereinafter.

The invention accordingly comprises the elements and combinations ofelements, features of construction, and arrangements of parts which willbe exemplified in the structure hereinafter described, and the scope ofthe application of which will be indicated in the following claims.

In the accompanying drawing, in which is illustrated one of variouspossible embodiments of the invention,

Fig. 1 is a cross section showing a switch with the invention appliedthereto;

Fig. 2 is a plan view of Fig. 1, a cover being removed; and,

Fig. 3 is a cross section taken on line 3 3 of Fig. 2.

Similar reference characters indicate corresponding parts throughout theseveral views of the drawing.

This invention comprises an improvement upon the contact shown in myPatent 1,697,886, dated January 8, 1929 and assigned to SpencerThermostat Company of Cambridge, Massachusetts.

Referring now more particularly to Fig. 1, there is illustrated atnumeral 1 a switch base assembly carrying line` terminals 3 arranged toclose a circuit 5 when gaps 7 therebetween are closed by contactors 9,said contactors 9 being mounted upon a snap-acting plate or bulged disc11.

The disc 11 is supported for vertical movement on a verticallyreciprocable pin 13. Vertical movement of the pin 13 is effected by apart connected at 15 but not shown. A cover 17 over the disc 11 carriesa reaction fulcrum or projection 19, circular in form. Upward movementof the pin 13 causes the bulged disc 11 to strike the projection 19,causing the disc to be thrown to a reverse curvature from that shown,this taking place with an over-centering snap-action and setting up areaction at the fulcrum 19 and between the contactors 9 and lineterminals 3, thus suddenly closing the circuit. Opening is accomplishedby drawing down the pin 13, whereupon the increased reaction at thecontacts 9 sets up a. 50 reversal of curvature so that the disc 11 snapsto the shape shown. thereby opening the circuit.

A pin 21 ensures proper allocation of the contacts and circuit gaps.

The device above described comprises a multicontacter switch in whichthe contactors are carried on a resilient member (disc 11) of such anature that for most perfect operation it should not be eccentricallysprung, as for instance by uneven contact pressure. In order thatperfect and even contact maybe had at each of the plurality of contacts,they are built and applied as follows:

Suitable openings 23 are placed through the disc 11 at the properlocations for the contacts. Extending through each opening 23, withample clearance is a tapering stem 25 which forms an extension from abutton 27, the button carrying between it and the disc 11 a mica orother insulating washer 29, the opening in the washer being such thatbefore upsetting a head 31 on the 80 stem 25, the washer 29 will forcethereover with a tight t, as shown. After application of the stem 25with its applied washer 29, a second similar washer 30 is applied abovethe disc 11. Then a metal washer 33 is applied and the extension 25 85upset as shown at numeral 31. The upsetting forces the metallic washer33 to the inverted conical shape shown, or that washer may initially begiven such a shape. The riveting clamps together the button 27 andwasher 33, thereby 90 forcing together the mica washers 29 and 30 andthus insulating the contact 9 from the disc 11.

It is preferable that the upsetting 'be done under heated conditions(preferably electrically) so that the mica is caused to take its shapebetter. Inasmuch as the switch nally operates under high temperaturecondition, this insures that the clearances are adapted to operatingconditions.

On its lower face, the button 2'7 is provided with 100 an extension 37.This extension passes slidably and loosely through the contact 9. Thelooseness permits swiveling of the plate. A head 41 prevents the plate 9from falling oi.

On the upper face of the plate 9 is peripherally 105 fastenedautogenously or by soldering or the like a metal cupped or arched spring39, which is herein shown as a bulged disc reacting against the button27. Operation is as follows:

When the switch is in open position (Figs. 1 110 and 3), the spring 39reacts against the button 27 tol take up lost motion and set thecontact' 9 in a definite and predetermined position.

's es When the switch closes, one contact may strike, before another. Inthis event its spring disc 39 is pressed flat, or substantially so, topermit alignment. the head 4l moving down from the contact Furthermore,the invention prevents the con-- tacts from hanging indifferently ontheir 'necessarily swiveljoints and ensures that allcontacts will belmade substantially at once. This is because of the springs 39accurately'predetermining the positions of the contacts. f v

e Another feature is that the spring 39 itself has a characteristicquick action which, when the main disc 11 is snapping up, maintainscontact until the snap action of spring 39 carries the contact quicklyand finally from the line terminals ,3,l thus providing a quick breakwith minimum y arcing.

The spring 39 has a relationship between displacement and force whereinthe force decreases with displacement so that it takes less force tohold the spring 39 against the-contact 9 than to start its displacementtoward a flat condition. Thus the kinetic energyinthe main discll atsnapping is used for starting and finishing deiiection of the spring 39but after closure of the switch (under static conditions) only a smallforce is required to hold down the spring 39. Thus there is not asubstantial tendency to force the main disc 11 to snap back when itshould not (as at a wrong temperature), as would be the case were a coilor other conventional type of spring used which requires increasingforce for increasing displacements thereof. Another way of stating thisfeature is that it required less force to hold the spring 39 in asubstantially, iiat or strained position (as when the switch is closed)than it does to drive it from its cupped or unstrained position (as whenthe switch is open). Likewise less force is required for maintaining anycomparativelymore strained position than any comparatively less strainedposition. Thus it functions llike a snap acting or quick vacting'cuppeddisc which does not over-center.

The simplicity of construction and the compactness thereof is evident,the whole'taking up substantially no more space than a springless type.o i

In view of the above, it will be seen that the several objects of theinvention are achieved andother advantageousresults attained.

As many changes could be made in carrying' fbe interpreted as.illustrative and not in a limiting sense. v

vIV claim: l 1 1'. A switch comprising vline contactseiecting at leastone gap, at least one contact therefor,

means for driving the contact-into engagement and at least one springbetween the driving means' and said contact, said spring beingcharacterized by requiring less force to hold it in a substantiallystrained position than to distort it froma predetermined less, strainedposition and comprising a member shaped to join the contact at spacedpoints and being arched between said points, the driving means drivinglthe spring from above and against said arch.

2v. Aswitch comprising line contacts effecting at least one gap, atleast one contact therefor. means for driving the contact intoengagement and at least one spring between the driving means and saidcontact, said spring being characterized by requiringless force to holdit in a substantially strained position than to distort it from apredetermined less strained position and comprising an arched discjoined peripherally to the contact, said driving means driving the disc.

3. A switch comprisingfa main snapping disc,`

a plurality of contacts, swivel means for holding said contacts to thedisc and resilient means for predeterminately positioningl each contact.

4. A switch comprising a main snapping disc, a plurality of contacts,swivel means for-holding said contacts to the disc and resilient means.for predeterminately positioning each contact comprising resilient meansbetween each contact and its holding means.

5. A switch comprising a main snapping disc, I a plurality of contacts,swivel means for holding f ing a quick-acting, bulged spring engagingits respective contact at spaced points.

7. A switch comprising a main snapping disc, a plurality of contacts,swivel means for holding said contacts to the disc and resilient meansfor predeterminately positioning each contact comprising resilient meansbetween each contact and its holding means, said resilient meanscomprising a quick-acting, bulged-disc spring peripherally engaging saidcontact.

8. A switch comprising a main snapping disc,

a plurality of contacts, swivel means for holding said contacts to thedisc and resilient means for predeterminately positioning each contactcomprising resilient means between each contact and its holding means,said resilient means comprising a quick-acting, bulged-disc springperipherally engaging said contact, the contact having a swivelingconnection with the holding means.

JOHN A. SPENCER.

